The possible oxidation states of $Tl$ are

The $+1$ oxidation state in group $13$ and $+2$ oxidation state in group $14$ become more stable with increasing atomic number. Explain.

Rationalize the given statements and provide chemical reactions:
$1$. Lead $(II)$ chloride reacts with $Cl_2$ to give $PbCl_4$.
$2$. Lead $(IV)$ chloride is highly unstable towards heat.
$3$. Lead is known not to form an iodide,$PbI_4$.

Which of the following is used to obtain $Ag$ from $AgNO_3$?

Assertion : White phosphorus is more reactive than red phosphorus.
Reason : Red phosphorus consists of $P_4$ tetrahedral units linked to one another to form linear chains.

$P_4O_{10}$ cannot be used to dry $NH_3$ because ..............